Objective: To evaluate the effect of exogenous luteinizing hormone in in vitro fertilization cycles with depot GnRH agonist and low residual LH levels. Design: Prospective randomized clinical trial. Setting: 2nd Department of Gynecology and Obstetrics, Medical Faculty and L. Pasteur University Hospital Košice Methods: In the prospective randomized clinical trial the effect of exogenous LH on outcomes of assisted reproduction was evaluated. The total number of 68 in vitro fertilization cycles in normogonadotrophic women undergoing assisted reproduction with GnRH agonist down-regulation and recombinant FSH controlled ovarian stimulation were included. In all cycles the low residual LH level in the middle of stimulation was detected. The cycles were randomized into three groups. The first group was stimulated with pure recombinant FSH. In the second group the exogenous LH activity in the form of human menotrophin was added. And in the third group the human recombinant LH was added. Results: Better outcomes of assisted reproduction were detected in both groups with exogenous LH activity. But these results, except the dosage of FSH, were not statistically significant. The increase of pregnancy rate by more than one fifth in these both groups can be considered as clinically relevant. Conclusions: It can not be positively proved at the base of our results that exogenous LH activity in cycles with low residual LH level can improve outcomes of assisted reproduction. It could be appropriate in the future to select women that can profit from exogenous LH activity according to other parameters not only to the LH serum level.

        Key words: IVF, luteinizing hormone, controlled ovarian stimulation